Aralkylation of aromatics with styrenes



United States Patent ()fiice 3,069,478 Patented Dec. 18, 1962 3,069,478 ARALKYLATION F AROMATICS WITH STYRENES Robert L. McLaughlin, Woodbury, N.J., assignor to Socony Mobil Oil Company, Inc., a corporation of New York No Drawing. Filed Mar. 1, 1960, Ser. No. 11,960 12 Claims. (Cl. 260-649) This invention relates to the production of substituted aromatic hydrocarbon derivatives. It is more particularly concerned with a catalytic process for reacting styrene and substituted styrenes with aromatic hydrocarbons.

As is well known to those skilled in the art a reaction between an olefinic hydrocarbon and an aromatic hydrocarbon, wherein a hydrogen of the aromatic ring is re placed by an alkyl group, is a form of alkylation reaction. When the olefin has an aromatic substitutent, as in the case of styrene, the reaction with an aromatic hydrocarbon is called an aralkylation reaction. The term is used in this sense in the specification and claims. In the case of styrene itself the reaction is referred to as ;styrenation herein. It has been proposed to aralkylate or to styrenate aromatic hydrocarbons in the presence I of strong sulfuric acid catalyst. Such processes have been disadvantageous, because they require time-consuming, laborious process steps to remove the sulfuric acid and its degradation products. Further the sulfuric acid catalyzes polymerization of the aromatic olefin (e.g. styrene), thereby causing unreasonable loss in the process.

It has now been found that aromatic hydrocarbons can be aralkylated readily with good yield. It has been discovered that aromatic hydrocarbons can be aralykylated with styrene and its derivatives in the presence of certain solid catalysts that can be removed by simple filtration.

Accordingly, it is an object of this invention to provide a process for aralkylating aromatic hydrocarbons. Another object is to provide a catalytic process for aralkylating aromatic hydrocarbons. A specific object is to provide a catalytic process for aralkylating aromatic hydrocarbons in the presence of a solid catalyst. Another specific object is to provide a catalytic process for sty-renating alkylbenzenes. Other objects and advantages of this invention will become apparent to those skilled in the art, from the following detailed description.

In general, this invention provides a process for aralkylating aromatic hydrocarbons that comprises reacting a styrene reactant with an alkyl aromatic hydrocarbon, in the presence of a catalyst selected from the group consisting of acid-treated clay of the montmorillonite type and synthetic silica-alumina containing between about 7 percent and about 15 percent alumina by weight, at a temperature varying between about 60 C. and about 150 C.; the molar ratio of said alkyl aromatic hydrocarbon to said styrene reactant being at least about 1:1 and the amount of catalyst being between about one percent and about 5 percent of the weight of the total reactants.

The styrene reactants contemplated herein are styrene and its ring-substituted derivatives. The ring s ubstituents can be lower alkyl, halogen, i.e. substituents other than those which normally hinder alkylation reactions, such as amino groups which poison or react with the catalyst. Non-limiting examples of the styrene reactants are styrene, vinyltoluene (punethylstyrene), and dichlorostyrene.

The alkyl aromatic hydrocarbons utilizable herein are generally the alkylbenzenes, although alkyl naphthalenes can be used. The alkyl aromatic hydrocarbons can have up to three alkyl groups. The substituent alkyl groups can be straight chain or branched chain and can have up to 18 carbon atoms per alkyl groups. However, the low er alkyl groups, i.e. butyl and lower, are preferred. Nonlimiting examples of the aromatic hydrocarbon reactant are toluene, cumene, cymene, xylene, trimethylnaphthalene, ethylbenzene, methylnaphthalene, diethylbenzene, and butylbenzene.

The catalysts utilizable herein are acid activated mont morillonite type clay and synthetic composites of silica and alumina. In the runs described hereinafter a nonswelling bentonite clay of the montmorillonite type, which has been activated by acid treatment to give a composition:

Al Si O (OH) .nH O

was used. This product is available in the activated state under the trade name Super Filtrol. The acid activation treatment is well known to those skilled in the art and is described more or less in detail by B. A. Stagner in The Science of Petroleum, volume III, page 1699 (Oxford Press) (1938). For the activation of small quantities of clay a similar treatment may be used. Thus, one kilogram of bentonite is boiled with 2,000 cubic centimeters of 17 percent sulfuric acid for three hours. The mixture is filtered and the clay washed with distilled water until the filtrate is substantially free from acid (0.2 to 0.5 percent acid). The clay is then dried to a moisture content of about 15 percent and ground to pass a ZOO-mesh screen. When the acid treated clay is washed with hard water after the acid is neutralized, the clay is injured by absorbing basic ions from the Water.

When only a portion of the total extractable material is leached from the clay by the acid, the maximum activity is developed. The optimum concentration of the acid is about 15 percent to about 20 percent. Sulfuric and hydrochloric acid are the most economical to use although sulfuric acid is somewhat slower than hydrochloric.

The other type of material found effective as a catalyst herein are synthetic composites of silica and alumina which are acidic in nature. Such composites will contain about 7 percent and about 15 percent, by weight, of alumina, the balance being substantially silica. There appears to be nothing critical about the manner in which these composites are prepared. They may be made by any of the usual methods well known to those skilled in the manufacture of catalysts. A feasible method for preparing the catalyst involves adding an aqueous acidic solution, containing the required amount of aluminum salt, to an aqueous solution of sodium silicate, thus precipitating the silica and alumina simultaneously. This type of operation can becarried out in accordance with the method known in United States Patent No. 2,384,946 to produce the catalyst in a hydrogel bead form.

Another modified form of the synthetic silica-alumina composite is one having incorporated into the silicaalumina sol a small amount of powdered material insoluble in the sol. Such catalysts are described in United States Letters Patent No. 2,900,349.

The basic, and preferred, aralykylation involved herein is the 1:1 molar addition reaction. As illustrated with styrene and xylene, the desired product is xylylphenylethane (i.e. a monostyrenated product). This material and the related 1:1 products from using other styrenes or aromatic hydrocarbons are good secondary plasticizers for polyvinyl resins, such as polyvinyl chloride. The distyrenated product is, to some extent, also useful as a polyvinyl resin plasticizer, usually when used together with the monostyrenated product. Higher alkylation products are not deemed desirable. Accordingly, the process of this invention is controlled to produce a major amount of monostyrenated product, a smaller amount of distyrenated product, and a minimum amount of higher alkylated, or polymer, products.

Therefore, the efiiciency of the process is measured upon the basis of the amount of aromatic hydrocarbon xylylphenylethane boiling at 380 C. at 760 mm. mercury pressure and fraction 2 was distyrenated xylene (dimethylbenzylxylene) boiling at 450 C. at 760 mm. mercury pressure. The residue was a mixture of higher theoretically required to produce 100% monostyrenated 5 styrenated and polymeric material. Pertinent results are product in relation to the amount of aromatic hydrocarset forth in Table I.

TABLE I Reactants, grams Products, grams Xylene Etfi- Example Weight Temp, reacted, ciency, Percent G. g. Percent Styrene Xylene Catalyst Fracti0n1Fraction2 Residue 208 500 1. 4 60 47 38 171 48 23 208 500 10 1. 4 so 165 77 62 104 51 208 500 10 1. 4 125 252 48 37 129 61 208 500 10 1. 4 135 263 73 12 140 66 2023 500 10 1. 4 125-150 271 58 21 141 67 208 500 10 1. 4 150 240 59 16 107 50 205 1, 000 25 2. 1 135 328 44 10 174 82 208 1, 000 25 2. 1 150 300 45 18 s 75 bon actually reacted. As all the styrene reactant is con- 20 From the data in Table I, it will be noted that the sumed in the process, the greater the amount of polyprocess of this invention is operable at temperatures as styrenated material and polymer there is formed the low as about 60 C. and as high as about 150 C. Preferless will be the amount of aromatic hydrocarbon reacted. ably, the reaction is carried out at temperatures varying Thus, when the bulk of the product is polystyrenated between about 135 C. and about 150 C. The run of matter and polymer (as in Example 1, infra),the amount Example 7 was made under the optimum conditions of aromatic hydrocarbon (xylene, in Example 1) consumed will be small and the efficiency (amount aromatic hydrocarbon reacted X 100 divided by theoretical amount aromatic hydrocarbon for 100% 1:1 product) will be low (23%, in Example 1). Complete, 100 percent efficiency, of course, is attained when all the product is 1:1 addition product.

REACT ING STYRENE WITH XYLENE- TEMPERATURE EFFECT found to obtain maximum yield of desired product. EFFECT OF CATALYST CONCENTRATION Examples 9 and 10 A series of runs were made reacting xylene and styrene in the presence of acid-treated montmorillonite type clay catalyst. These runs were made using the procedure described for the runs of Examples 1 through 8. The variant in these runs was catalyst concentration. Pertinent data and results are set forth in Table II. For comparison, the data for the run of Example 6 are also tabulated.

TABLE II Reactants, grams Products, grams Xylene Effi- Example Weight Temp, reacted, ciency,

Percent 0. g. Percent Styrene Xylene Catalyst Fractionl Fracti0n2 Residue were reacted in the presence of acid-treated clay of the montmorillonite type (Super Filtrol) as the catalyst. In

each run, a different combination of reactant ratio, cata- 5O lyst ratio, and temperature was used. The pertinent data thereon are set forth in Table I.

In each run, the xylene and clay catalyst were charged to a reaction vessel and agitated. The xylene-clay mixture was heated to the reaction temperature indicated for the run and styrene was added portionwise over a period of about 2 hours. As the reaction was exothermic, the rate of addition was adjusted so that little or no external heating or cooling was needed. After the styrene was all added, the reaction mixture was maintained at the selected temperature for an additional one-half to one hour to insure complete reaction of the styrene. The mixture was cooled and filtered to remove the catalyst. The filtrate was topped to remove unreacted xylene and then vacuum-distilled. Fraction 1 was It will be noted that concentrations of catalyst, based upon total charge, as low as 0.7 weight percent are effective. Higher catalyst concentrations are, however, more effective. Generally, the reaction can be carried out using catalyst weight concentrations varying between about 0.7 percent and about 5 percent, and preferably between about 2 percent and about 3 percent for maximum yields.

EFFECT OF SOLVENT CONCENTRATION Examples 11 and 12 Runs were made reacting styrene and Xylene in the presence of acid-treated montmorillonite type clay catalyst, using the procedure described for the runs of Examples 1 through 8. The variant in these runs was the amount of xylene to show the efiect of the presence of xylene in excess of the stoichiometric amount. Pertinent data are set forth in Table III together with data from the run of Example 6, for comparison purposes.

TABLE III Reactants, grams Products, grams Weight Temp, Xylene Efli- Example percent 0. reacted, ciency,

Styrene Xylene Moles Catalyst Fraction Fraction Residue g. percent excess 1 2 208 212 None 10 2. 4 150 176 82 18 32 208 500 2. 7 10 1. 4 150 240 59 16 107 50 208 1,000 7. 4 10 0. 9 150 274 49 10 59 From the data of Table IH, it is noted that when 11) with no excess xylene diluent, the efl'iciency of the reaction is relatively low. As more diluent, excess xylene 6 and yields are not generally so great as with styrene. The general and optimum conditions, however, are of the same magnitude as with styrene.

Examples 17 Through 22 m f tf f In i a gg 5 These examples show the elfect of temperature variae ecnve 1 i g 1S em: 0 use tions. Runs were made reacting vinyltoluene (pmethyl- W mo mo es excess styrene) and xylene at various temperatures in the presmatlc on f fi 8% th m ence of acid-activated montmorillonite type clay catai time? 1 i q i lyst, using the general procedures of Examples 1 through of t 6 reaction e fi ac or V6 15 e we 10 9. In these runs, fraction 1 (m0no-methylstyrenated (and, thus, thet lrne) of addltlon oft e styrene reactant. product) boiled at 3550 under 760 millimeters T00 P addltlon W111 lower the efficlel'lcya f f of cury pressure, and fraction 2 (di-methylstyrenated prodgreater polymerization and faster reduction of dilution. not) boiled at 435 c under 7 0 millimeters mercury In general, the reactlon can be carried out in between pressure. Pertinent data and results are set forth in about one hour and about 5 hours. Table V.

TABLE V Reactants, grams Products, grams Weight Temp, Xylene Efii- Example percent 0. reacted, ciency, Vmyl- Xylene Catalyst Fraction Fraction Residue g. percent toluene 1 2 235 1, 000 2. 0 s0 s7 99 as 43 23 235 1, 000 25 2. 0 100 193 94 34 25 235 1, 000 25 2. 0 120 253 57 15 104 49 177 750 20 2. 2 135 205 34 2s 57 235 1, 000 25 2. 0 140 309 41 21 135 54 177 750 20 2. 2 150 201 44 15 83 52 AROMATICS OTHER THAN XYLENE Examples 23 and 24 Examples 13 gh'16 These runs show the effect of catalyst concentration. Runs were made reacting aromatic hydrocarbon 25 Runs were made reacting vinyltoluene (p-methylstyrene) actants other than xylene with styrene in the presence of a11d Xylene the P 3551166 P the afild'tfeated montmofllacid-treated montmorillonite type clay. The procedure 10mm yp 3 catalyst, 115mg the Procfidure of Examples used was like that of Examples 1 through 9. Pertinent 17 through 22. The variant was catalyst concentration. data, reactants, and results are set forth in Table IV. Pertinent data and results, in comparison with those of TABLE IV Reactants, grams Products, grams Weight Temp, Aromatic Elfi- Example Aromatic per- O. reacted, eieney, Styrene Aromatic Catalyst cent Fraition Fragtion Residue g. percent;

The data of Table IV show that the reaction is effective Example 21, are set forth in Table VI.

TABLE VI Reactants, grams Products, grams Weight Temp, Xylene Efii- Example percent C. reacted, ciency, Vinyl- Xylene Catalyst Fraction Fraction Residue g. percent toluene 1 2 235 1, 000 10 o. s 237 53 7 104 4a 235 1, 000 25 2. 0 140 309 41 21 135 54 235 1, 000 50 4. 0 140 255 71 7 90 42 with various alkylaromatic hydrocarbons. Benzene, how- Examples 25 and 26 YF Z does.not appear to be utlhzable m the process of These examples show the efiect of solvent concentrat 13 mvemwn' 70 tion. Runs were made reacting vinyltoluene (methyl- USE OF VINYLTOLUENE styrene) and xylene in the presence of the acid-treated montmorillonite type clay catalyst, using the procedure of Examples 17 through 21. Pertinent data and results, in comparison with those of example 21, are set forth in Table VII.

TABLE VII Reactants, grams Products, grams Weight Temp, Xylene Efii- Example Percent C. reacted, ciency, Vinyl- Xylene Moles Catalyst Fraction 1 Fraction 2 Residue g. Percent toluene Excess USE OF DICHLOROSTYRENE AND OF OTHER CATALYSTS Example 27 Examples 28 and 29 As described in Examples 1 through 9, runs were made wherein the catalyst was a synthetic silica-alumina containing about 10 weight percent alumina (catalyst of Example 10 of United States Patent No. 2,900,349). Pertinent data and results are set forth in Table VIII.

4. The process defined in claim 3, alkyl benzene is xylene.

5. The process defined in claim 3, alkyl benzene is cumene.

6. The process defined in claim 3, alkyl benzene is cymene.

7. The process defined in claim 3, alkyl benzene is toluene.

8. The process defined in claim 3, alkyl benzene is diethylbenzene.

9. A process for aralkylating aromatic hydrocarbons that comprises reacting vinyltoluene with xylene, in the presence of an acid-activated clay of the montmorillonite type, at a temperature varying between about 135 C. and about 150 C.; the molar ratio of said xylene to said vinyltoluene being between about 3:1 and about 9:1 and the amount of said acid-treated clay being between about wherein said lowerwherein said lowerwherein said lowerwherein said lowerwherein said lower- IABLE VIII Reactants, grams Products, grams Efl'i Example Weight Temp, Xylene eiency, Percent C. reacted Percent Styrene Xylene Catalyst Fraction 1 Fraction 2 Residue l Diehlorostyrene. 2 Clay. 3 Silica-alumina.

Although the present invention has been described with preferred embodiments, it is to be understood that modifications and variations may be resorted to, without departing from the spirit and scope of this invention, as those skilled in the art will readily understand. Such variations and modifications are considered to be within the purview and scope of the appended claims.

What is claimed is:

1. A process for aralkylating aromatic hydrocarbons that comprises reacting a styrene reactant with an alkyl aromatic hydrocarbon, in the presence of a catalyst selected from the group consisting of an acid-treated clay of the montmorillonite type and synthetic silica-alumina containing between about 7 percent and about 15 percent alumina by weight, at a temperature varying between about 60 C. and about 150 C.; the molar ratio of said .alkyl aromatic hydrocarbon to said styrene reactant being at least about 1:1 and the amount of said catalyst being between about 0.7 percent and about 5 percent of the weight of total reactants.

2. The process defined in claim 1, wherein said alkyl aromatic hydrocarbon reactant is a lower-alkyl benzene.

3. A process for aralkylating aromatic hydrocarbons that comprises reacting styrene with a lowcr-alkyl benzene, in the presence of an acid-treated clay of the montmorillonite type, at a temperature varying between about 135 C. and about 150 C.; the molar ratio of said loweralkyl benzene to said styrene being between about 3:1 and about 9:1 and the amount of said acid-treated clay being between about 0.7 percent and about 5 percent of the weight of the total reactants.

0.7 percent and about 5 percent of the weight ofthe total reactants.

10. A process for aralkylating aromatic hydrocarbons that comprises reacting dichlorostyrene with xylene, in the presence of an acid-treated clay of the montrnorillonite type, at a temperature varying between about C. and about C.; the molar ratio of said xylene to said dichlorostyrene being between about 3:1 and about 9:1 and the amount of said acid-treated clay being between about 0.7 percent and about 5 percent of the weight of the total reactants.

11. A process for aralkylating aromatic hydrocarbons that comprises reacting styrene with a lower-alkyl benzene, in the presence of a synthetic silica-alumina containing between about 7 percent and about 15 percent alumina by weight, at a temperature varying between about 135 C. and about 150 C.; the molar ratio of said lower-alkyl benzene to said styrene being between about 3:1 and about 9:1 and the amount of said silicaalumina being between about 0.7 percent and about 5 percent of the weight of the total reactants.

12. The process defined in claim 11, wherein said lower-alkyl benzene is xylene.

References Cited in the file of this patent UNITED STATES PATENTS 2,564,488 Mahan Aug. 14, 1951 2,767,230 Brown et al. Oct. 16, 1956 2,930,820 Aries Mar. 29, 1960 FOREIGN PATENTS 585,073 Great Britain Jan. 29, 1947 

1. A PROCESS FOR ARALKYLATING AROMATIC HYDROCARBONS THAT COMPRISES REACTING A STYRENE REACTANT WITH AN ALKYL AROMATIC HYDROCARBON, IN THE PRESENCE OF A CATALYST SELECTED FROM THE GROUP CONSISTING OFAN ACID-TREATED CLAY OF THE MONTMORILLONITE TYPE AND SYNTHETIC SILICA-ALUMINA CONTAINING BETWEEN ABOUT 7 PERCENT AND ABOUT 15 PERCENT ALUMINA BY WEIGHT, AT A TEMPERATURE VARYING BETWEEN ABOUT 60* C. AND ABOUT 150* C.; THE MOLAR RATIO OF SAID ALKYL AROMATIC HYDROCARBON TO SAID STYRENE REACTANT BEING AT LEAST ABOUT 1:1 AND THE AMOUNT OF SAID CATALYST BEING BETWEEN ABOUT 0.7 PERCENT AND ABOUT 5 PERCENT OF THE WEIGHT OF TOTAL REACTANTS. 